磷钨钒杂多酸催化α-甲基丙烯酸甲酯酯交换反应的研究

Studies on catalytic synthesis of unsaturated ester using phosphotungstic heteropoly acid

利用差示扫描量热法(DSC)测定Dawson型磷钨钒杂多酸对甲基丙烯酸甲酯的阻聚效果,选择其中阻聚性能最佳的杂多酸.以α-甲基丙烯酸甲酯和正丁醇为原料,在不加任何阻聚剂的条件下,以阻聚性能最佳的杂多酸为催化剂,通过酯交换法合成α-甲基丙烯酸丁酯单体,采用正交实验探讨了影响反应的主要因素,确定了合成α-甲基丙烯酸丁酯的最佳工艺条件:n(α-甲基丙烯酸甲酯)∶n(正丁醇)=1.2∶1,磷钨钒杂多酸催化剂用量为反应液总量的0.6%,反应时间为8 h,反应温度为125℃.在此条件下,α-甲基丙烯酸丁酯的收率可达90%以上.用红外光谱和核磁共振谱对产物进行了结构表征,证实其结构与用常规酯化法合成的产物并无明显差异.

The inhibition effects of vanadium substituted Dawson-type acid（W,P） on the polymerization methyl methacrylate（MMA） were measured to choose the best performance inhibitor heteropoly acid by differential scanning calorimetry（DSC）.In the presence of the best performance inhibitor Phosphotungstic heteropoly acid catalyst,α-Butyl methacrylate monomer was prepared by transesterification of α-Methyl methacrylate and n-butanol as starting materials.The optimum conditions which determined by orthogonal experiment were as follows：the molar ration of α-Methyl methacrylate to n-butanol was 1.2∶1,weight of heteropolyacid was 0.6% of total weight,reaction time was 8 h,reaction temperature was 125℃.Under the optimum conditions,the yield was about 90%.The product which characterized by IR and NMR was confirmed that the structure were not different from the product synthesis by conventional esterification.